Fin field-effect transistor (FinFET) devices include a transistor architecture that uses raised source-to-drain channel regions, referred to as fins. A FinFET device can be built on a silicon-on-insulator (SOI) substrate, where a semiconductor material, such as silicon, is patterned into a fin-like shape and functions as the channel of the transistor.
A gate can be wrapped around and over the fin. A double or dual gate structure includes a gate oxide and gate contact formed on two sides of the channel. A 3D or tri-gate FinFET includes a gate structure wrapped on three sides of a fin. Gate-all-around FinFETs include gate structures that surround the channel region on all sides, e.g., on all four sides of the fin.
Gate-all-around FinFETs have improved electrostatics over tri-gate or double-gate devices due to improved gate control. However, nanowires tend to have a smaller perimeter than fins, and also larger external resistance due to the under-spacer component.